Modeling Diffusion of Sparsely Populated Acids on a Monomer/Polymer Lattice Andrew Brzezinski, Matthew Duch Dept. of Materials Science & Engineering Spring 2006

Background & Motivation Acid generation by multi-beam laser interference Results in an FCC lattice-type illumination pattern Unit cell on the order of the wavelength of light used ( = 351 – 532 nm) sample

Background & Motivation Acid acts as catalyst for polymerization of photoresist Resulting structure reflects illumination intensity

Code: Initialization Used alternate unit cell than standard FCC 400x400x566 sites Acid placement based on sum of 13 Gaussian distributions Acid distribution proportional to intensity

Code: Movement Get next acid from list Polymerize? Pick direction Move Acid Is target monomer? Compare to RND Is target polymer? Move Acid Pass Fail

Code: Data Analysis Label each lattice site Create list of bonded sites Collapse list to determine cluster size and number of bonds Number of polymerized sites with 0-6 number of bonds Total number of clusters Bin clusters by size Largest cluster size Images of lattice

Determine Parameters Movement probability into polymerized bin Polymerization probability

Determine Parameters Movement probability into polymerized bin: 0.3 Polymerization probability: 0.5

Cluster Size Dependence

Bond Numbers 16 I 0 I0I0

In Conclusion Made a model to capture basic physics of polymer cross-linking Used our model with acid distribution from interference lithography Have shown that our model has potential to increase our understanding and control of the fabrication process